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Sprite Masking and Overflow Test ROM

From Sega Retro

Gens-gs-r7plus-vdp-to-cpp-86948622-SpriteMaskingTestRom.png

Nemesis' Sprite Masking and Overflow Test ROM is a test ROM used to verify the emulation of several Sega Mega Drive VDP quirks, including sprite limits.

Tests

The following tests are performed by the Sprite Masking and Overflow Test ROM.

Terminology:

  • H32 == 256x224 display mode
  • H40 == 320x224 display mode.
  • Sprite mask: A sprite with X=0.

Tests:

  1. Max Sprites Per Line: 16 in H32, 20 in H40.
  2. Max Sprite Dots - Basic: Up to 256 sprite dots in H32; 320 in H40.
  3. Max Sprite Dots - Complex: Same as previous, except it verifies that sprites are cut off in the middle.
  4. Sprite Mask: Verifies that lower-priority sprites are masked if a sprite mask exists and is not the first sprite on the line.
  5. Sprite Mask S1: Verifies that lower-priority sprites are *not* masked if a sprite mask exists and is the first sprite on the line.
  6. Mask S1 On Dot Overflow: Verifies that sprite masks at the beginning of the line are ineffective if sprite dot overflow occurs on the previous line.
  7. Mask S1,X=1 S2,X=0: Verifies that the non-existent sprite masking "Mode 2" is not implemented.
  8. Mask S1,X=40 S2,X=0: Same as previous.
  9. Max Sprites Per Frame: 64 in H32, 80 in H40.

For tests with two results, the left result indicates that the minimum boundary is respected, and the right result indicates that the maximum boundary is respected.

Test #6 is conditional on test #5 passing. If test #5 passes, then test #6 passing is an error (indicated by a red line underneath "PASS").

Downloads

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Download Sprite Masking and Overflow Test ROM
Multiple downloads available

Test results

Hardware

Emulators

Note: Using latest versions of emulators, unless otherwise stated.

Emulator Release date H32 Mode H40 Mode Comments
AGES
BizHawk
BlastEm
D-DGen
DebuGens
DGen
DrMD
DualGens
Exodus
FB Alpha
GenaDrive
Genecyst 1998-08-18
SMaOTR H32 Genecyst.png
SMaOTR H40 Genecyst.png
GenEm (DOS) 1997-05-20
SMaOTR H32 GenEm.png
SMaOTR H40 GenEm.png
Images are cropped to 320x200.
Generator (emulator)
Genesis Plus
Genesis Plus GX
Genesis4iphone
Genital
Gens
Gens (Nick o'DIMM)
Gens (XPort)
Gens KMod
Gens Plus! 2005-08-06
SMaOTR H32 GensPlus.png
SMaOTR H40 GensPlus.png
Gens Re-Recording
Gens Tracer
Gens X
Gens/GS 2009-11-22
SMaOTR H32 GensGS.png
Gens-gs-r7plus-vdp-to-cpp-86948622-SpriteMaskingTestRom.png
Gens/GS II 2016
SMaOTR H32 GensGS.png
Gens-gs-r7plus-vdp-to-cpp-86948622-SpriteMaskingTestRom.png
Gens32
Gensoid
Genux
GigaDrive (GP32)
HazeMD
Higan
IDC Log Gens
JEnesis
JEnesisDS
Kega
Kega (emulator)
Kega Fusion 2010-03-07
SMaOTR H32 KegaFusion.png
SMaOTR H40 KegaFusion.png
Kega Lazarus
KGen
KGen98
Mednafen
Megadrive Emulator
Megasis
Mimic
NeoGenesis
PGen
PicoDrive
PicoDrive (Windows)
PicoDriveDS
PSPGenesis
Regen
RetroCopy
RetroDrive
SegaEMU
SGens
St0rm
VGen
Xe
Xega
Xenesis

External links